President Barack Obama is trying to make it possible for Americans to keep their health insurance coverage if they like it. But his now-infamous promise may not be realistic.

Insurance experts say that, short of repealing the entire health care law, there are a number of obstacles that could keep insurers from letting customers renew old policies that the companies had planned to scrap for 2014. Here’s what you need to know if you have received a cancellation notice:

Q: What will my insurer do?

A: Your insurer likely doesn't know yet. Obama said Thursday that he would allow insurers to renew for at least a year existing policies that previously would have not have met the new law's requirements. After the companies expressed uncertainty and reservations about the change, Obama met with their CEOs on Friday.

Aetna Inc., the nation’s third-largest health insurer, plans to extend some of its canceled policies, but it hasn’t elaborated on that. Robert Laszewski, a health care industry consultant, said he expects other insurers to make a decision over the next few days on whether to let customers renew policies that the companies had decided to scrap.

Q: Can't insurers just continue the coverage they had in place?

A: The decision is far more complex. For starters, insurers would need to figure out how much to charge since they haven't set premiums or the price of coverage, for plans they expected to scrap. Prices typically change annually to cover inflation — not to mention the massive changes of an entirely new health care law.

They would also have to send letters to customers with canceled policies, telling them the coverage can now be renewed. And they would have to inform customers who want to keep canceled plans about any protections that are now required by the overhaul but are not included under the old plans.

Insurers then would have to wait for customers to decide whether to keep the coverage and respond. The final step would be to finalize rates and billing and reissue the policies.

All this adds up several months of work. But insurers would have to do all of it in about 30 days in order to have coverage ready to start on Jan. 1.

Q: Are there other reasons an insurer can't keep my plan?

A: Yes. State insurance regulators have to decide whether to allow insurers to do so. Many haven't made that call yet. The insurance commissioner for the state of Washington has already said he will not allow insurers to extend the old policies.

Aetna spokeswoman Susan Millerick said the company needs help from state regulators “to remove barriers that would make it difficult to make this change in such a short period of time.”

Q: What can I do if I don't get to renew my coverage?

A: Customers still have until Dec. 15 to use the overhaul's insurance exchanges to sign up for health insurance coverage that starts in January. The premiums may be higher because the law requires more extensive coverage than some plans currently offer. But customers also may be eligible for income-based tax credits to help them foot the bill.

Customers who do not qualify for a subsidy should look beyond the overhaul’s exchanges. They only show plans for which subsidies can be used, and an insurer may be able to make other options available.